Thin film piezoelectric micro-actuator for head gimbal assembly

ABSTRACT

A thin film piezoelectric (PZT) micro-actuator is disclosed. Two thin film pieces of PZT are couple to a slider support frame. The slider support frame has a slider support connected by a leading beam to a base. The two thin film pieces of PZT connect the slider support to the base. Applied voltage causes the thin film pieces of PZT to contract or expand, moving the slider support in relation to the base. The thin film pieces of PZT can be single or multiple layers. The thin film PZT micro-actuator can be coupled to the suspension by anisotropic conductive film, with the thin film pieces of PZT between the slider support frame and the suspension. Alternately, the thin film PZT micro-actuator can be coupled to the suspension with the thin film pieces of PZT exterior to the slider support frame and the suspension.

BACKGROUND INFORMATION

The present invention is directed to micro-actuators used in hard diskdrive head gimbal assemblies. More specifically, the present inventionpertains to thin film piezoelectric micro-actuators.

FIG. 1 illustrates a hard disk drive design typical in the art. Harddisk drives 100 are common information storage devices consistingessentially of a series of rotatable disks 104 that are accessed bymagnetic reading and writing elements. These data transferring elements,commonly known as transducers, are typically carried by and embedded ina slider body 110 that is held in a close relative position overdiscrete data tracks formed on a disk to permit a read or writeoperation to be carried out. The slider is held above the disks by asuspension. The suspension has a load beam and flexure allowing formovement in a direction perpendicular to the disk. The suspension isrotated around a pivot by a voice coil motor to provide coarse positionadjustments. A micro-actuator couples the slider to the end of thesuspension and allows fine position adjustments to be made.

In order to properly position the transducer with respect to the disksurface, an air bearing surface (ABS) formed on the slider body 110experiences a fluid air flow that provides sufficient lift force to“fly” the slider 110 (and transducer) above the disk data tracks. Thehigh speed rotation of a magnetic disk 104 generates a stream of airflow or wind along its surface in a direction substantially parallel tothe tangential velocity of the disk. The air flow cooperates with theABS of the slider body 110 which enables the slider to fly above thespinning disk. In effect, the suspended slider 110 is physicallyseparated from the disk surface 104 through this self-actuating airbearing. The ABS of a slider 110 is generally configured on the slidersurface facing the rotating disk 104 (see below), and greatly influencesits ability to fly over the disk under various conditions.

FIG. 2 a illustrates a micro-actuator with a U-shaped ceramic frameconfiguration 201. The frame 201 is made of, for example, Zirconia. Theframe 201 has two arms 202 opposite a base 203. A slider 204 is held bythe two arms 202 at the end opposite the base 203. A strip ofpiezoelectric material 205 is attached to each arm 202. A bonding pad206 allows the slider 204 to be electronically connected to acontroller. FIG. 2 b illustrates the micro-actuator as attached to anactuator suspension flexure 207 and load beam 208. The micro-actuatorcan be coupled to a suspension tongue 209. Traces 210, coupled along thesuspension flexure 207, connect the strips of piezoelectric material 205to a set of connection pads 211. Voltages applied to the connection pads211 cause the strips 205 to contract and expand, moving the placement ofthe slider 204. The suspension flexure 207 can be attached to a baseplate 212 with a hole 213 for mounting on a pivot via a suspension hinge214. A tooling hole 215 facilitates handling of the suspension duringmanufacture and a suspension hole 216 lightens the weight of thesuspension.

FIG. 3 illustrates a prior art method for coupling a slider 204 to amicro-actuator 201. Two drops of epoxy or insulative adhesive 301 areadded to both sides of the slider 204. The slider 204 may then beinserted into the U-shaped micro-actuator. The back surfaces of theslider 204 and the micro-actuator 201 are kept at the same heightthroughout the curing process.

The manufacture of a U-shaped frame is very difficult. The epoxy bondingprocess is difficult to control, leading to problems with performance.Additionally, the frame itself is bulky, with poor shock performance anda tendency for particle generation and electrostatic damage. Slider tiltduring the manufacturing process can create problems with the headgimbal assembly static control. A large amount of voltage is needed todrive the micro-actuator. All this leads to a general poor performanceby the U-shaped micro-actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a hard disk drive design typical in the art.

FIG. 2 illustrates a typical head gimbal assembly having a U-shapedmicro-actuator.

FIG. 3 illustrates a prior art method for coupling a slider to amicro-actuator.

FIGS. 4 a-c illustrate one embodiment of a thin film PZT micro-actuatorcoupled to a head gimbal assembly, according to the present invention.

FIGS. 5 a-b illustrate one embodiment of a thin film PZT micro-actuator,according to the present invention.

FIG. 6 illustrates one embodiment of a multiple layer thin film piece ofpiezoelectric material.

FIGS. 7 a-b illustrate various embodiments of the operation of the thinfilm pieces of PZT.

FIGS. 8 a-c illustrate the effect of the driving voltage on themicro-actuator.

FIG. 9 illustrates in a flowchart one embodiment for fabricating a headgimbal assembly with a thin film PZT micro-actuator according to thepresent invention.

FIGS. 10 a-e illustrates in a series of diagrams one embodiment forfabricating a head gimbal assembly with a thin film PZT micro-actuatoraccording to the present invention.

FIG. 11 illustrates one embodiment of using anisotropic conductive filmin the bonding process between the thin film pieces of PZT and thesuspension tongue.

FIGS. 12 a-e illustrate in graph form the results of tests comparing thethin film PZT micro-actuator to a traditional U-shaped micro-actuator.

FIGS. 13 a-d illustrate an alternate embodiment for thin film PZTmicro-actuator according to the present invention.

DETAILED DESCRIPTION

A thin film piezoelectric (PZT) micro-actuator is disclosed. Two thinfilm pieces of PZT are couple to a metal T-shaped support frame. TheT-shaped slider support frame has a slider support connected by aleading beam to a base. The two thin film pieces of PZT connect theslider support to the base. Applied voltage causes the thin film piecesof PZT to contract or expand, moving the slider support in relation tothe base. The thin film pieces of PZT can be single or multiple layers.The thin film PZT micro-actuator can be coupled to the suspension byanisotropic conductive film, with the thin film pieces of PZT betweenthe T-shaped slider support frame and the suspension. Alternately, thethin film PZT micro-actuator can be coupled to the suspension with thethin film pieces of PZT exterior to the T-shaped slider support frameand the suspension.

FIGS. 4 a-c illustrate one embodiment of a thin film PZT micro-actuatorcoupled to a head gimbal assembly. FIG. 4 a shows a detailedillustration of one embodiment of the micro-actuator coupled to thesuspension tongue 209. The slider 204 is coupled to a T-shaped slidersupport frame 401. In one embodiment, the T-shaped slider support frameis made of metal. A thin film piece of PZT 402 is coupled to each sideof the T-shaped slider support frame 401 to act as a positioncontroller. By applying a controlled voltage to each thin film piece ofPZT 402, the thin film pieces of PZT 402 are made to expand or contract,causing the front end of the T-shaped slider support frame 401 to bepulled to the left or to the right. In one embodiment, the slider iscoupled to the T-shaped slider support frame by anisotropic conductivefilm (ACF), which electrically couples the slider as well as physically,reducing the likelihood of electrostatic damage. In another embodiment,the slider is physically coupled to the T-shaped slider support frame byUV resin or adhesive and electrically coupled by an silver epoxy orresin. A suspension outrigger 403 supports the T-shaped slider supportframe 401. The slider 204 is also electrically connected to a set ofbonding pads 206 mounted on a connection plate 404. The slider 204 iselectrically connected to the set of bonding pads 206 by gold ballbonding or solder ball bonding 405. The micro-actuator is connected to aset of traces 406 leading back to the connection pads 211. Voltages sentalong these traces 406 can be used to control the micro-actuator. FIG. 4b shows one embodiment of the micro-actuator connected to head gimbalassembly. In this embodiment, the set of bonding pads 206 are connectedto a set of traces 210 leading to the connection pads 211. FIG. 4 cshows in a side view the micro-actuator as connected to a suspension. Aparallel gap 407 is maintained between the suspension outrigger 403 andthe T-shaped slider support frame 401, allowing the micro-actuator tomove smoothly. The parallel gap can be between 35 and 50 μm. Thesuspension outriggers 403 and a dimple 407 focus the load force on thecenter of the slider 204.

FIGS. 5 a-b illustrate one embodiment of a thin film PZT micro-actuator.FIG. 5 a illustrates one embodiment of the T-shaped slider support frame401 and the thin film pieces of PZT 402. In one embodiment, the slidersupport frame has a base 501 coupled to a slider support 502 by aflexible leading beam 503. The base 501 and the flexible leading beam503 act as a swing support. The base 501 can be used as a datum foralignment purposes when coupling the micro-actuator to the suspension.The leading beam 503 bends to allow the slider support 502 to be movedin a horizontal swinging movement by the thin film pieces of PZT 402 inrelation to the base 501. In one embodiment, the width of the leadingbeam 503 is narrower than the base 501 and the slider support 502. Theslider support 502 is flanked by side beams 504 to be attached to thethin film pieces of PZT 402. The thin film pieces of PZT each have anelectrical bonding pad 505 that allow an electrical signal to be input.In one embodiment, the thin film pieces of PZT have a common groundingpad 506. In one embodiment, the thin film pieces of PZT 402 are combinedwith the T-shaped slider support frame 401 to form the thin film PZTmicro-actuator 507 illustrated in FIG. 5 b. The sides of the thin filmpieces of PZT 402 opposite the electrical bonding pads 505 are coupledto the top of the base 501. In one embodiment, the thin film pieces ofPZT 402 have an insulation layer (not shown) on each side. Theinsulation layers only expose the bonding pad. These insulation layersprotect the thin film of PZT 402 to prevent electrical shorts duringcoupling of the metal T-shaped slider support frame and suspension. Thethin film pieces of PZT 402 have one end coupled to the base and theother end coupled to the side beams 504 of the slider support 502.

The thin film pieces of piezoelectric material can have a single layeror multiple layers. FIG. 6 illustrates one embodiment of a multiplelayer thin film piece of PZT 402. The first layer 601 is a base supportductile material, such as a polymide, to protect the PZT and increasethe shock performance. The third and seventh layer 602 is a PZT. Thethird and seventh layers 602 are surrounded by PZT electric layers 603and 604, representing the second, fourth, sixth, and eighth layers.These PZT electric layer 603 and 604 can be made of platinum, gold, orother similar metals. An insulative adhesive, such as epoxy, layer 605,acting as the fifth layer, couples the fourth and sixth layers 604 toeach other. The exterior PZT electric layers 603 are coupled to a firstbonding pad 606. The interior PZT electric layers 604 are couple to asecond bonding pad 607.

FIGS. 7 a-b illustrate various embodiments of the operation of the thinfilm pieces of PZT. FIG. 7 a shows one embodiment of a micro-actuator507 in which the two thin film pieces of PZT have matching polarities. Afirst thin film piece of PZT 701 and a second thin film piece of PZT 702are polarized in the same direction. The first thin film piece of PZT701 has a first input pad 703, the second thin film piece of PZT 702 hasa second input pad 704, and the two thin film pieces of PZT have acommon ground 705. A first sine voltage 706 is input to the first inputpad 703 and an opposed phase sine voltage 707 is input to the secondinput pad 704 to drive the micro-actuator. FIG. 7 b shows one embodimentof a micro-actuator 507 in which the two thin film pieces of PZT haveopposing polarities. The first thin film piece of PZT 708 and the secondthin film piece of PZT 709 are polarized in opposite directions. Asingle sine voltage 710 is input to the first input pad 703 and thesecond input pad 704 to drive the micro-actuator.

FIGS. 8 a-c illustrate the effect of the driving voltage on themicro-actuator. FIG. 8 a shows the micro-actuator 507 and slider 204with no voltage being applied. FIG. 8 b shows one embodiment of themicro-actuator 507 and slider 204 with voltage applied. The first thinfilm piece of PZT 801 is receiving a negative voltage, causing it toshrink. The second thin film piece of PZT 802 is receiving a positivevoltage, causing it to extend. This causes the T-shaped slider supportframe 401 to bend to the left. FIG. 8 c shows an alternate embodiment ofthe micro-actuator 507 and slider 204 with voltage applied. The firstthin film piece of PZT 801 is receiving a positive voltage, causing itto extend. The second thin film piece of PZT 802 is receiving a negativevoltage, causing it to shrink. This causes the T-shaped slider supportframe 401 to bend to the right.

One embodiment for fabricating a head gimbal assembly with a thin filmPZT micro-actuator 507 is illustrated by FIG. 9 in a flowchart and FIGS.10 a-f in a series of diagrams. The process starts (Block 910) with aT-shaped slider support frame 401 and two thin film pieces of PZT 402,as shown in FIG. 10 a. Each thin film piece of PZT 402 has an electricalbonding pad 505 and a ground pad 506 common to both thin film pieces. Asshown in FIG. 10 b, the two thin film pieces of PZT 402 are attached tothe T-shape slider support frame 401 to create the thin film PZTmicro-actuator 507 (Block 920). FIG. 10 c illustrates one embodiment ofa suspension on which to mount the thin film PZT micro-actuator 507. Inone embodiment, the suspension tongue 209 of the suspension has anelectrical bonding pad 1001 for each thin film piece of PZT 402, as wellas a grounding pad 1002. The suspension electrical bonding pads 1001 areeach electrically linked to a micro-actuator trace 406.

One option for attaching the thin film PZT micro-actuator is the use ofanisotropic conductive film. In one embodiment shown in FIG. 10 d, alayer of ACF 1003 is placed across the suspension tongue. In oneembodiment shown in FIG. 11, anisotropic conductive film 1101 is used inthe bonding process by forming a layer between the thin film pieces ofPZT 402 and the suspension tongue 209. The micro-actuator electricalbonding pads 505 are aligned with the suspension electrical bonding pads1001. The micro-actuator grounding pad 506 is aligned with thesuspension grounding pad 1002. A pressure of 30-200 MPa and atemperature of 60-400 Celsius are applied to form the bond. The metalgrains in the anisotropic conductive film create an electricalconnection, while an insulative adhesive, such as epoxy, creates aphysical bond.

Returning to FIG. 9, the thin film PZT micro-actuator 507 is thenattached to the suspension tongue 209 by the two thin film pieces of PZT402 (Block 930), as shown in FIG. 10 e. The static and dynamicperformance of the thin film PZT micro-actuator 507 is tested to screenout defects (Block 940). As shown in FIG. 10 f, the slider 204 isattached to the thin film PZT micro-actuator 507 at the slider support502 (Block 950). In one embodiment, slider 204 is bonded to the slidersupport 502 using anisotropic conductive film. The slider 204 iselectrically bonded to the bonding pads 206 of the suspension (Block960). In one embodiment, the slider is electrically bonded using goldball bonding or solder ball bonding 405. The static dynamic performanceof the slider is then tested (Block 970). If no defects are found, theprocess is completed (Block 980).

FIGS. 12 a-e illustrate in graph form the results of some of these testsas compared to a traditional U-shaped micro-actuator. FIG. 12 a showsthe displacement in micrometers in response to the voltage applied. Afirst test 1201 was run with the thin film PZT micro-actuator and asecond test 1202 was run with traditional micro-actuator. FIG. 12 bshows the resonance gain in decibels at various frequencies in kilohertzfor the present invention. A first measurement 1203 is taken by excitingthe base plate. A second measurement 1204 is taken by exciting the PZT.FIG. 12 c shows the resonance gain in decibels at various frequencies inkilohertz for the prior art. A first measurement 1205 is taken byexciting the base plate. A second measurement 1206 is taken by excitingthe PZT. Due to the mass effect, a small gain, from 6-10 dB, is shown inthe resonance by the present invention over the prior art. FIG. 12 dshows the resonance phase in degrees at various frequencies in kilohertzfor the present invention. A first measurement 1207 is taken by excitingthe base plate. A second measurement 1208 is taken by exciting the PZT.FIG. 12 e shows the resonance gain in decibels at various frequencies inkilohertz for the prior art. A first measurement 1209 is taken byexciting the base plate. A second measurement 1210 is taken by excitingthe PZT. Again only a small gain, from 6-10 dB, is shown in theresonance by the present invention over the prior art.

FIGS. 13 a-f illustrate an alternate embodiment for thin film PZTmicro-actuator. As shown in FIG. 13 a, a T-shaped slider support frame401 and two thin film pieces of PZT 402 are assembled. The two thin filmpieces of PZT 402 are coupled to the T-shaped slider support frame 401to form a thin film PZT micro-actuator 507, as shown in FIG. 13 b. FIG.13 c illustrates one embodiment of a suspension on which to mount thethin film PZT micro-actuator 507. In one embodiment, the suspensiontongue 209 of the suspension has an electrical bonding pad 1001 for eachthin film piece of PZT 402, as well as a grounding pad 1002. Thesuspension electrical bonding pads 1001 are each electrically linked toa micro-actuator trace 406. In one embodiment shown in FIG. 13 d, alayer of ACF 1003 is placed across the suspension tongue. As shown inFIG. 13 e, the thin film PZT micro-actuator 507 is coupled to thesuspension tongue 209 by the base 501 of the T-shaped slider supportframe 401. The thin film pieces of PZT 402 are exterior to the T-shapedslider support frame 401 and the suspension in this embodiment. Asupport layer (not shown) can be inserted between the base 501 and thesuspension tongue 209 to maintain a parallel gap. As shown in FIG. 13 f,a wire 1301 couples each micro-actuator electrical bonding pad 505 tothe corresponding suspension electrical bonding pad 1001. The wire 1301can be coupled to the electrical bonding pads by gold ball bonding orsilver ball bonding 1302. Similarly, as shown in FIG. 13 c, themicro-actuator grounding pad 506 is coupled by a wire 1303 to thesuspension grounding pad 1002.

1-10. (canceled)
 11. A magnetic head gimbal assembly, comprising: aslider having a magnetic head for reading and writing data onto and froma magnetic disk, a suspension for providing the slider, a proximalportion of which is attached to an actuator arm of a coarse adjustmentactuator for positioning the slider on the magnetic disk; amicro-actuator disposed on the suspension for a fine adjustment of theslider; a flexible circuit electrically coupled to the slider and themicro-actuator; wherein the micro-actuator having a slider support framecoupled to the suspension with a slider support to hold the slider and aswing support to allow at least a horizontal swinging movement of theslider support; and a position controller connecting the slider supportframe to control the position of the slider.
 12. A magnetic head gimbalassembly of claim 11, wherein the slider support further comprises: afirst side beam and a second side beam disposed respectively on eachside of the slider support to couple the position controller to theslider support frame.
 13. A magnetic head gimbal assembly of claim 11,wherein the swing support includes: a base to couple the suspension; anda leading beam connecting between the slider support and the base tosupport the horizontal swinging movement of the slider support.
 14. Amagnetic head gimbal assembly of claim 13, wherein the leading beam hasa narrower width than the slider support or the base.
 15. A magnetichead gimbal assembly of claim 11, wherein the positioning controllerincludes: a first thin film piece of piezoelectric material coupled tothe first side of the slider support frame; and a second thin film pieceof piezoelectric material coupled to the second side of the slidersupport frame.
 16. A magnetic head gimbal assembly of claim 12, whereinthe positioning controller includes: a first thin film piece ofpiezoelectric material coupled to the first side beam of the slidersupport; and a second thin film piece of piezoelectric material coupledto the second side beam of the slider support.
 17. A magnetic headgimbal assembly of claim 15, further comprising: a first micro-actuatorelectrical bonding pad electrically coupled to the first thin film pieceof piezoelectric material; a second micro-actuator electrical bondingpad electrically coupled to the second thin film piece of piezoelectricmaterial; and a micro-actuator grounding pad electrically coupled to thefirst thin film piece of piezoelectric material and the second thin filmpiece of piezoelectric material, and the suspension includes: a firstsuspension electrical bonding pad coupled to a first micro actuatortrace; a second suspension electrical bonding pad coupled to a secondmicro actuator trace; and a suspension grounding pad.
 18. A magnetichead gimbal assembly of claim 17, further comprising: an anisotropicconductive film to physically couple the first thin film piece ofpiezoelectric material and the second thin film piece of piezoelectricmaterial to the suspension and to electrically couple the firstmicro-actuator electrical bonding pad to the first suspension electricalbonding pad, the second micro-actuator electrical bonding pad to thesecond suspension bonding pad, and the micro-actuator grounding pad tothe suspension grounding pad.
 19. A magnetic head gimbal assembly ofclaim 17, further comprising: an insulative adhesion material tophysically couple the swing support to the suspension; a bonding wire toelectrically couple the first micro-actuator electrical bonding pad tothe first suspension electrical bonding pad, the second micro-actuatorelectrical bonding pad to the second suspension bonding pad, and themicro-actuator grounding pad to the suspension grounding pad.
 20. Amagnetic head gimbal assembly of claim 15, wherein the first thin filmpiece of piezoelectric material and the second thin film piece ofpiezoelectric material have matching polarities or opposing polarities.21. A magnetic head gimbal assembly of claim 15, wherein the first thinfilm piece of piezoelectric material and the second thin film piece ofpiezoelectric material have one or more layers.
 22. A magnetic headgimbal assembly of claim 21, wherein the first thin film piece and thesecond thin film piece include: a first layer of ductile material; athird and seventh layer of piezoelectric material above the first layer;a second, fourth, sixth, and eighth layer of thin electric materialsurrounding the third and seventh layers; and a fifth layer of aninsulative adhesion material coupling the fourth layer to the sixthlayer.
 23. A magnetic disk apparatus, comprising: a disk to storeinformation; a magnetic head to read information to and writeinformation from the disk; a suspension to support the magnetic head,the suspension including a load beam flexible in a directionsubstantially perpendicular to the disk; a coarse adjustment actuator todrive said suspension; a micro-actuator for micro motion mounted in amicro-actuator mounting portion provided on said suspension; and whereinthe micro-actuator having a slider support frame disposed on thesuspension with a slider support to hold the slider and a swing supportto support at least a horizontal swinging movement of the slidersupport; and a positioning controller connecting the slider supportframe to control the position of the slider.
 24. A magnetic diskapparatus of claim 23, wherein the slider support further comprises: afirst and a second side beams disposed respectively on the both side ofthe slider support to couple the positioning controller to the slidersupport frame.
 25. A magnetic disk apparatus of claim 23, wherein theswing support having: a base to couple to the suspension; and a leadingbeam coupling the slider support to the base to support the horizontalswinging movement of the slider support.
 26. A magnetic disk apparatusof claim 25, wherein the width of the leading beam is narrower than thewidth of the slider support and the base.
 27. A magnetic disk apparatusof claim 23, wherein the positioning controller having: a first thinfilm piece of piezoelectric material connecting to the first side of theslider support frame; and a second thin film piece of piezoelectricmaterial connecting to the second side of the slider support frame. 28.A magnetic disk apparatus of claim 24, wherein the positioningcontroller comprises: a first thin film piece of piezoelectric materialconnecting to the first side beam of the slider support; and a secondthin film piece of piezoelectric material connecting to the second sidebeam of the slider support.
 29. A magnetic disk apparatus of claim 27,further comprising: a first micro-actuator electrical bonding padelectrically coupled to the first thin film piece of piezoelectricmaterial; a second micro-actuator electrical bonding pad electricallycoupled to the second thin film piece of piezoelectric material; and amicro-actuator grounding pad electrically coupled to the first thin filmpiece of piezoelectric material and the second thin film piece ofpiezoelectric material, and the suspension includes: a first suspensionelectrical bonding pad coupled to a first micro actuator trace; a secondsuspension electrical bonding pad coupled to a second micro actuatortrace; and a suspension grounding pad.
 30. A magnetic disk apparatus ofclaim 29, further comprising: an anisotropic conductive film tophysically couple the first thin film piece of piezoelectric materialand the second thin film piece of piezoelectric material to thesuspension and to electrically couple the first micro-actuatorelectrical bonding pad to the first suspension electrical bonding pad,the second micro-actuator electrical bonding pad to the secondsuspension bonding pad, and the micro-actuator grounding pad to thesuspension grounding pad.
 31. A magnetic disk apparatus of claim 29,further comprising: an insulative adhesion material to physically couplethe swing support to the suspension; a bonding wire to electricallycouple the first micro-actuator electrical bonding pad to the firstsuspension electrical bonding pad, the second micro-actuator electricalbonding pad to the second suspension bonding pad, and the micro-actuatorgrounding pad to the suspension grounding pad.
 32. A magnetic diskapparatus of claim 29, wherein the first thin film piece ofpiezoelectric material and the second thin film piece of piezoelectricmaterial have matching polarities, and the first micro-actuatorelectrical bonding pad and the second micro-actuator bonding pad receiveopposing electrical signals through the first and the second suspensionelectrical bonding pads.
 33. A magnetic disk apparatus of claim 29,wherein the first thin film piece of piezoelectric material and thesecond thin film piece of piezoelectric material have opposingpolarities, and the first micro-actuator electrical bonding pad and thesecond micro-actuator bonding pad receive synchronous electrical signalsthrough the first and the second suspension electrical bonding pads. 34.A magnetic disk apparatus of claim 27, wherein the first thin film pieceof piezoelectric material and the second thin film piece ofpiezoelectric material have one or more layers.
 35. A magnetic diskapparatus of claim 27, wherein the first thin film piece and the secondthin film piece include: a first layer of ductile material; a third andseventh layer of piezoelectric material above the first layer; a second,fourth, sixth, and eighth layer of thin electric material surroundingthe third and seventh layers; and a fifth layer of an insulativeadhesion material coupling the fourth layer to the sixth layer.